Re: [PATCH 06/12] pci: epf-test: Simplify transfers result print

[Manivannan Sadhasivam <mani@kernel.org>]

On Wed, Feb 15, 2023 at 12:21:49PM +0900, Damien Le Moal wrote:
> In pci_epf_test_print_rate(), instead of open coding a reduction loop to
> allow for a disivision by a 32-bits ns value, simply use div64_u64() to
> calculate the rate. To match the printed unit of KB/s, this calculation
> divides the rate by 1000 instead of 1024 (that would be KiB/s unit).
> 
> The format of the results printed by pci_epf_test_print_rate() is also
> changed to be more compact without the double new line. dev_info() is
> used instead of pr_info().
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

Thanks,
Mani

> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 42 ++++++++-----------
>  1 file changed, 17 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index e07868c99531..f630393e8208 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -297,34 +297,23 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test)
>  	return;
>  }
>  
> -static void pci_epf_test_print_rate(const char *ops, u64 size,
> +static void pci_epf_test_print_rate(struct pci_epf_test *epf_test,
> +				    const char *op, u64 size,
>  				    struct timespec64 *start,
>  				    struct timespec64 *end, bool dma)
>  {
> -	struct timespec64 ts;
> -	u64 rate, ns;
> -
> -	ts = timespec64_sub(*end, *start);
> -
> -	/* convert both size (stored in 'rate') and time in terms of 'ns' */
> -	ns = timespec64_to_ns(&ts);
> -	rate = size * NSEC_PER_SEC;
> -
> -	/* Divide both size (stored in 'rate') and ns by a common factor */
> -	while (ns > UINT_MAX) {
> -		rate >>= 1;
> -		ns >>= 1;
> -	}
> -
> -	if (!ns)
> -		return;
> +	struct timespec64 ts = timespec64_sub(*end, *start);
> +	u64 rate = 0, ns;
>  
>  	/* calculate the rate */
> -	do_div(rate, (uint32_t)ns);
> +	ns = timespec64_to_ns(&ts);
> +	if (ns)
> +		rate = div64_u64(size * NSEC_PER_SEC, ns * 1000);
>  
> -	pr_info("\n%s => Size: %llu bytes\t DMA: %s\t Time: %llu.%09u seconds\t"
> -		"Rate: %llu KB/s\n", ops, size, dma ? "YES" : "NO",
> -		(u64)ts.tv_sec, (u32)ts.tv_nsec, rate / 1024);
> +	dev_info(&epf_test->epf->dev,
> +		 "%s => Size: %llu B, DMA: %s, Time: %llu.%09u s, Rate: %llu KB/s\n",
> +		 op, size, dma ? "YES" : "NO",
> +		 (u64)ts.tv_sec, (u32)ts.tv_nsec, rate);
>  }
>  
>  static int pci_epf_test_copy(struct pci_epf_test *epf_test, bool use_dma)
> @@ -400,7 +389,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test, bool use_dma)
>  		kfree(buf);
>  	}
>  	ktime_get_ts64(&end);
> -	pci_epf_test_print_rate("COPY", reg->size, &start, &end, use_dma);
> +	pci_epf_test_print_rate(epf_test, "COPY", reg->size, &start, &end,
> +				use_dma);
>  
>  err_map_addr:
>  	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr);
> @@ -481,7 +471,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test, bool use_dma)
>  		ktime_get_ts64(&end);
>  	}
>  
> -	pci_epf_test_print_rate("READ", reg->size, &start, &end, use_dma);
> +	pci_epf_test_print_rate(epf_test, "READ", reg->size, &start, &end,
> +				use_dma);
>  
>  	crc32 = crc32_le(~0, buf, reg->size);
>  	if (crc32 != reg->checksum)
> @@ -567,7 +558,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test, bool use_dma)
>  		ktime_get_ts64(&end);
>  	}
>  
> -	pci_epf_test_print_rate("WRITE", reg->size, &start, &end, use_dma);
> +	pci_epf_test_print_rate(epf_test, "WRITE", reg->size, &start, &end,
> +				use_dma);
>  
>  	/*
>  	 * wait 1ms inorder for the write to complete. Without this delay L3
> -- 
> 2.39.1
> 

-- 
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